Tree-structured parzen estimator optimized-automated machine learning assisted by meta-analysis for predicting biochar-driven N2O mitigation effect in constructed wetlands.

Biochar is a carbon-neutral tool for combating climate change. Artificial intelligence applications to estimate the biochar mitigation effect on greenhouse gases (GHGs) can assist scientists in making more informed solutions. However, there is also evidence indicating that biochar promotes, rather than reduces, N2O emissions. Thus, the effect of biochar on N2O remains uncertain in constructed wetlands (CWs), and there is not a characterization metric for this effect, which increases the difficulty and inaccuracy of biochar-driven alleviation effect projections. Here, we provide new insight by utilizing machine learning-based, tree-structured Parzen Estimator (TPE) optimization assisted by a meta-analysis to estimate the potency of biochar-driven N2O mitigation. We first synthesized datasets that contained 80 studies on global biochar-amended CWs. The mitigation effect size was then calculated and further introduced as a new metric. TPE optimization was then applied to automatically tune the hyperparameters of the built extreme gradient boosting (XGBoost) and random forest (RF), and the optimum TPE-XGBoost obtained adequately achieved a satisfactory prediction accuracy for N2O flux (R2 = 91.90%, RPD = 3.57) and the effect size (R2 = 92.61%, RPD = 3.59). Results indicated that a high influent chemical oxygen demand/total nitrogen (COD/TN) ratio and the COD removal efficiency interpreted by the Shapley value significantly enhanced the effect size contribution. COD/TN ratio made the most and the second greatest positive contributions among 22 input variables to N2O flux and to the effect size that were up to 18% and 14%, respectively. By combining with a structural equation model analysis, NH4+-N removal rate had significant negative direct effects on the N2O flux. This study implied that the application of granulated biochar derived from C-rich feedstocks would maximize the net climate benefit of N2O mitigation driven by biochar for future biochar-based CWs.

Development and initial validation of classification for severe spinal deformity based on X-ray features.

PURPOSE: To develop a clinically feasible classification for severe spinal deformity based on X-ray features. METHODS: A total of 223 consecutive severe spinal deformity cases who underwent corrective operation were enrolled from 2004 to 2015 retrospectively. Based on X-ray features, a novel classification was developed containing three components: curve types, curve angle and apex location. There were five curve types as follows: single scoliosis (SS), kyphoscoliosis (KS), angular deformity (AD), long curve (LC), and double curves (DC). Curve angle subsection on coronal and sagittal planes including A:90-109, B:110-129, C:130-149, D: > 150. Apex location means the exact level of apex located. Reliability of the classification was tested. RESULTS: The kappa values for inter-observer and intra-observer reliability of the curve types, curve angle, and apex level were larger than 0.80. X-ray classification for overall patients with severe spinal deformity showed that there were 101 SS cases, 47 KS, 46 AD, 19 LC and 10 DC. For the curve angle, there were grade A 123 cases, B 43, C 18, D 15 on coronal plane and grade A 38, B 17, C 16, and D 19 on sagittal plane. Apex location showed there were 27 patients at T7 or upper levels, 31 on T8, 58 on T9, 45 on T10, 18 on T11, and 44 at T12 or lower levels. CONCLUSION: A novel classification for severe spinal deformity was described based on X-ray morphology. A high value for inter-observer and intra-observer reliability was shown. Each subgroup has its particular influence on decision-making and prognostic prediction.

Feasibility of microwave ablation of the vertebral growth plate for spine growth regulation: a preliminary study.

PURPOSE: To explore the feasibility of microwave ablation (MWA) of the vertebral growth plate as a minimally invasive treatment for early-onset scoliosis. MATERIALS AND METHODS: One side of the L1-L3 vertebral growth plates were ablated using different MWA powers. Ablation safety and size were examined. Subsequently, L1-L3 vertebral growth plates were ablated on one side for 40 s at 20 W. At 2, 4, and 6 weeks after the ablation, growth changes of the spine were observed. RESULTS: No piglets died during and after ablation, and all had modified Tarlov Grade 5. The safe MWA time (time for safely ablating the vertebral growth plate) was 17.0 ± 1.5 s at 50 W, 23.0 ± 2.3 s at 40 W, 31.0 ± 3.1 s at 30 W, 47.0 ± 3.7 s at 20 W, 70.0 ± 4.2 s at 15 W, and 158.0 ± 5.0 s at 10 W. With power <15 W, the vertebral growth plate could not be effectively ablated within the safe ablation time. Within the safe ablation times, the MWA size on hematoxylin and eosin slices on a transverse diameter was between 7 and 10 mm; and that on longitudinal diameter was mainly determined by the ablation needle length. Moreover, the growth plate and annulus fibrosus on the ablated side grew poorly over time, the vertebral body showed significant wedge-shaped changes, and the spine showed significant unbalanced growth. CONCLUSION: MWA of the vertebral growth plate can be performed safely when accompanied with appropriate thermometry, and could be a new minimally invasive strategy in regulating spine growth.

Effect of Spinal Shortening for Protection of Spinal Cord Function in Canines with Spinal Cord Angulation.

BACKGROUND Posterior vertebral column resection (PVCR) has been widely used as a treatment for severe spinal deformity. By using the canine model of vertebral column resection, this study explored the effect of spinal shortening on blood flow and function of the spinal cord during spinal cord angulation. MATERIAL AND METHODS The canine model of L1 vertebral column resection was constructed with the PVCR technique. The canines were divided into 5 groups according to the degree of shortening: the 0/4 group, the 1/4 group, the 2/4 group, the 3/4 group, and the control group. Spinal cord blood flow, neuroelectrophysiology, HE staining, nitric oxide, and endothelin-1 were measured during the procedure of vertebral column resection and spinal cord angulation. RESULTS The results showed that, in the 1/4 group and the 2/4 group, the blood flow of the spinal cord decreased by 16.5% and 10.6%, respectively, with no obvious damage in the spinal cord; in the 0/4 group and the 3/4 group, the blood flow decreased by 23.5% and 23.1%, respectively, with significant damage in the spinal cord. CONCLUSIONS When the spinal cord is shortened by 1/4 to 2/4, the tolerance of the spinal cord can increase and spinal cord injury resulting from angulation can be avoided. However, when the shortening reaches 3/4, it is harmful to the spinal cord. Proper shortening of the spinal cord by 1/4 to 2/4 may increase the tolerance of the spinal cord to the damage caused by angulation during PVCR.

Intraspinal neural axis abnormalities in severe spinal deformity: a 10-year MRI review.

PURPOSE: Documents indicated that the average prevalence of intraspinal neural axis abnormalities (INAAs) in presumed idiopathic scoliosis (PIS) patients was about 17.7%. However, paucity study focuses on the incidence of INAAs in severe spinal deformity (SSDs). In this study, we investigate the incidence of intraspinal neural axis abnormalities (IINAAs) and the clinical relevance in SSD at a single center. METHODS: All the patients with SSDs admitted for spinal surgery were evaluated from 2003 to 2014. INCLUSION CRITERIA: patients who present with coronal Cobb over 90° (and/or the sagittal Cobb ≥ 90°); patients with whole spine magnetic resonance imaging (MRI) done preoperatively; and patients with documented clinical findings preoperatively. EXCLUSION CRITERIA: ankylosing spondylitis, adult onset scoliosis, scoliosis secondary to bone destruction, and spinal dysraphism. RESULTS: 101 patients fulfilled the criteria were included. 43 patients were detected with INAAs (42.6%, 43/101). The most common INAAs was syrinx (S) (16/43, 37.2%). Of which, 43.7% (7/16), 37.5% (6/16), and 18.7% (3/16) were spindle, slit, and swelling types, respectively. Most of them were located in thoracic (6/16, 37.5%) and cervical (5/16, 31.3%) region. MRI revealed Chiari malformation with syringomyelia (C + S) in ten patients (10/43, 23.2%), Chiari malformation (C) in 6 patients (6/43, 13.9%) and others in 11 patients (11/43, 25.6%). As to the etiology, most patients with INAAs were PIS (34/43, 79.1%). On clinical examination, 16 of 101 patients (16/101, 15.8%) had abnormal neurologic signs. 15 of 16 patients (15/16, 93.7%) with abnormal neurologic signs had INAAs on MRI. On the other hand, 28 of 43 patients (28/43, 65.1%) with INAAs on MRI presented neurologically intact. 28 of 85 patients (28/85, 32.9%) with neurologically intact were detected with INAAs on MRI. CONCLUSION: The incidence of INAAs in SSDs was 42.6%. 65.1% of them present intact neurologic status. The most common neural anomaly was syrinx. Preoperative whole spine MRI must be beneficial for SSDs even in the absence of neurological findings. These slides can be retrieved under Electronic Supplementary Material.

The effect from different numbers of segmental arteries ligation to the spinal cord in the clinical practice of posterior vertebral column resection correction.

PURPOSE: In using posterior vertebral column resection (PVCR) to treat severe kyphoscoliosis, it is unavoidable to ligate and cut off several segmental arteries (SAs) of the spinal cord for exposure and hemostasis, but which would raise the neurological risks. The aim of this study is to explore the changes of intraoperative spinal cord monitoring (IOM) following ligating different numbers of SAs in PVCR. METHODS: Twenty-one consecutive patients with severe kyphoscoliosis were included and treated by PVCR correction. In operation, according to ligate different numbers of SAs, the IOM changes were recorded, respectively. Examinations of the covariance between different numbers of SAs ligations and IOM changes were performed to reveal the effect to the spinal cord by SAs ligations. RESULTS: In all the 21 cases, averaging 1.9 pairs of SAs were ligated. With the increased numbers of ligations, SSEP amplitudes and latencies were changed more obviously: from 1 to 3 pairs ligations, the mean decreased percentages of amplitudes were from 53.20 to 78.15%, the mean increased percentages of latency were from 1.23 to 1.40%, and the mean durations of decreased SSEP amplitudes were from 3.23 to 5.2 min; but without abnormal MEP changes. None occurred postoperative or delayed neurological deficit. Correlation analysis identified significant correlations between the number of SAs ligation and decreased percentage of SSEP amplitude (r = 0.945, P < 0.0001), and between the number of SAs being ligated and the duration of SSEP change (r = 0.945, P = 0.0002). CONCLUSIONS: Following the increased number of SAs ligation, the amplitude of SSEP is decreased more obviously with a much longer duration of recovery and the risk to spinal cord will be increased greatly. In the PVCR correction on the basis of spinal shortening, the numbers of SAs ligations should be as less as possible for neurological safety.

Preoperative short-term traction prior to posterior vertebral column resection: procedure and role.

PURPOSE: Severe rigid spine deformity with sharp curve can be effectively corrected by posterior vertebral column resection (PVCR). Meanwhile, high risk of this procedure also has been recognized generally. The aim of this study is to review and evaluate the role of preoperative skull-femoral traction prior to PVCR for extremely severe rigid spinal deformity with sharp angular curve >150°. METHODS: Twelve cases with extremely severe rigid deformities and sharp curves were treated by skull-femoral traction before operation. For them, the mean preoperative major scoliotic curve and kyphosis were 153° (110°-168°) and 109° (61°-180°). Continuous skull-femoral traction in supine position was started 4 weeks before operation. In the process of traction, tolerance, neurologic status, deformity changes, etc., were reviewed and documented for analysis. PVCR were performed in all these patients for final and main correction. RESULTS: The final traction force in the 12 cases was 63% of body weight. After 4-week traction, the main scoliotic curve and kyphosis were decreased by 34 and 31%. In 1 week, main scoliotic curve and kyphosis were decreased by 19 and 15%. In 2 weeks, the major scoliosis curve was decreased by 11%, but kyphosis was unexpectedly increased by 4%. Deformity in the last 2 weeks was less significant than the first 2 weeks. After PVCR, the main scoliotic curve and kyphosis were improved 69 and 66%. No permanent neurological damage occurred. CONCLUSION: Preoperative skull-femoral traction effectively mitigates the neurological risks of PVCR for extremely severe rigid spinal deformity with sharp curve. During traction, scoliosis can be improved more significantly and easily than kyphosis.

The risk factors of neurologic deficits of one-stage posterior vertebral column resection for patients with severe and rigid spinal deformities.

PURPOSE: To determine the risk factors of neurologic deficits during PVCR correction, so as to help improve safety during and after surgery. METHODS: A consecutive series of 76 patients with severe and rigid spinal deformities who were treated with PVCR at a single institution between October 2004 and July 2011 were included in our study. Of the 76 patients, 37 were male and 39 female, with an average age of 17.5 years (range 10-48 years). There were 52 adolescent patients (with an age <18 years) and 24 adult patients (with an age ≥18 years). Preoperatively, postoperatively and 6 months after surgery, we performed systemically neurologic function evaluations of each patients through meticulous physical examination. Any new abnormality or deterioration in evaluation of neurologic function than preoperative is reckoned postoperative neurologic deficits. Ten variables that might affect the safety of neurologic deficits during PVCR procedures, including imaging factors, clinical factors and operational factors, were analyzed using univariate analysis. Then the variables with statistical difference were analyzed by using multi-factor unconditional logistic regression analysis. RESULTS: No patient in this series had permanent paraplegia and nerve root injury due to operation. Change of neurologic status was found in six patients after surgery. Results of single-factor comparison demonstrated that the following seven variables were statistically different (P < 0.05): location of apex at main curve (X 3), Cobb angle at the main curve at the coronal plane (X 4), scoliosis associated with thoracic hyperkyphosis (X 5), level of vertebral column resected (X 6), number of segmental vessels ligated (X 7), preexisting neurologic dysfunction (X 8), and associated with intraspinal and brain stem anomalies (X 9). The multi-factor unconditional logistic regression analysis revealed that X 8 (OR = 49.322), X 9 (OR = 18.423), X 5 (OR = 11.883), and X 6 (OR = 8.769) were independent and positively correlated with the neurologic deficit. CONCLUSIONS: Preexisting neurologic dysfunction, associated with intraspinal and brain stem anomalies, scoliosis associated with thoracic hyperkyphosis and level of vertebral column resected are independent risk factors for neurologic deficits during PVCR procedure.

Thoracic pedicle classification determined by inner cortical width of pedicles on computed tomography images: its clinical significance for posterior vertebral column resection to treat rigid and severe spinal deformities-a retrospective review of cases.

BACKGROUND: Posterior vertebral column resection (PVCR) is an effective alternative for treating rigid and severe spinal deformities. Accurate placement of pedicle screws, especially apically, is crucial. As morphologic evaluations of thoracic pedicles have not provided objective criteria, we propose a thoracic pedicle classification for treating rigid and severe spinal deformities. METHODS: A consecutive series of 56 patients with severe and rigid spinal deformities who underwent PVCR at a single institution were reviewed retrospectively. Altogether, 1098 screws were inserted into thoracic pedicles at T2-T12. Based on the inner cortical width of the thoracic pedicles, the patients were divided into four groups: group 1 (0-1.0 mm), group 2 (1.1-2.0 mm), group 3 (2.1-3.0 mm), group 4 (≥3.1 mm). The proportion of screws accurately inserted in thoracic pedicles for each group was calculated. Statistical analysis was also performed regarding types of thoracic pedicles classified by Lenke et al. (SPINE 35:1836-1842, 2010) using a morphological method. RESULTS: There were statistically significant differences in the rates of screws inserted in thoracic pedicles between the groups (P < 0.008) except groups 3 and 4 (P > 0.008), which were then combined. The accuracies for the three new groups were 35.05%, 65.34%, and 88.32%, respectively, with statistically significant differences between the groups (P < 0.017). Rates of screws inserted in thoracic pedicles classified by Lenke et al. (SPINE 35:1836-1842, 2010) were 82.31%, 83.40%, 80.00%, and 30.28% for types A, B, C, and D, respectively. There was no statistically significant difference (P > 0.008) between these types except between type D and the other three types (P < 0.008). CONCLUSIONS: The inner cortical width of thoracic pedicles is the sole factor crucial for accurate placement of thoracic pedicle screws. We propose a computed tomography-based classification of the pedicle's inner cortical width: type I thoracic pedicle: absent channel, inner cortical width of 0-1 mm; type II: presence of a channel of which type IIa has an inner cortical width of 1.1-2.0 mm and type IIb a width of ≥2.1 mm. The proposed classification can help surgeons predict whether screws can be inserted into the thoracic pedicle, thus guiding instrumentation when PVCR is performed.

A five-step remedial screw placement method to treat severe spinal deformity with free-hand transpedicular screw placement.

PURPOSE: Severe spinal deformity is a complex morphological deformation that occurs and develops in three-dimensional space combined with abnormal development and morphology of anatomical structures, which presents great difficulties in the process of transpedicular screw placement. This study tried to explore the methods of transpedicular screw placement in surgical correction of severe spinal deformities. METHODS: Surgical corrections through posterior approach were performed in all the 76 cases (mean age 20.4 years). The averaging preoperative Cobb's angle of scoliosis was 108.2° ± 33.6° (range 100°-170°). Among these patients, 34 cases were combined with kyphosis; the average Cobb's angle of kyphosis was 77.3° (range 63°-160°). During operation, the screw tract was first established with the regular free-hand pedicle screw placement method. When this failed, in order to adjust the screw trajectory, a five-step remedial method was performed in the following order: (1) the"funnel" method; (2) exploring the pedicle exterior edge through the costotransverse joint; (3) exploring the superior and inferior edges of pedicle through the nerve root canal; (4) the vertebral plate fenestration; and (5) hemilaminectomy. RESULTS: Among all 1,472 screws planned to be placed for the patients, 1,210 (82.2 %) were successfully placed after using the regular method, and 262 (17.8 %) failed in this stage. After applying the five-step remedial method, 256 of the failed 262 screws were successfully placed. Among them, 176 screws (68.8 %) were successfully placed after Step 1, 44 (17.2 %) after Step 2, 21 (8.2 %) after Step 3, 12 (4.7 %) after Step 4, and 3 (1.2 %) after Step 5. In only six, pedicles screws could not be placed eventually. No nerve or blood vessel damages occurred in all cases. All final screw positions were validated by CT. CONCLUSION: The five-step remedial method proved to be an effective supplementary method for transpedicular screw placement to treat patients with severe spinal deformities. The key points include a detailed preoperative plan, a meticulous hand drilling sensation, and an experienced probing technique for screw tract.

Quantifying biochar-induced greenhouse gases emission reduction effects in constructed wetlands and its heterogeneity: A multi-level meta-analysis.

Zero-waste biochar is an emerging tool for carbon neutralization, but the role of biochar in reducing greenhouse gases (GHGs) emissions from CWs were controversy and uncertainty. Yet, no previous study has integrated multiple research systems to quantitatively examine biochar-mediated GHGs emission reduction potential in CWs. Here we synthesized 114 studies to quantify biochar-induced declines ability of GHGs in the CWs by using the multi-level meta-analysis, reveal the variation of GHGs emission effect in different biochar-CWs and its response relationship with biochar, and identify the moderating variables that had a strong explanatory effect on the emission reduction effect of biochar. We showed that biochar remarkably affect CO2 mitigation (p < 0.05), but has insignificant and heterogeneous effects on CH4 and N2O. Pyrolysis time, influent dissolved oxygen (DO), influent NO3--N concentration, hydraulic retention time (HRT) and wetland type can significantly affect the effect of biochar on CH4 emission reduction. Particularly, the importance of HRT and wetland type was 0.89 and 0.85, respectively. Specially, the surface batch CWs modified by biochar could significantly promote the emission of CH4 (p < 0.001), and the effect size was up to 89.59. For N2O, biochar diameter, biochar addition ratio, influent COD/TN ratio, plant name, and removal efficiency of NO3--N/TN/COD were significant moderators. Among them, influent COD/TN ratio and plant name showed a stronger explanation. Planting Cyperus alternifolius L. significantly enhanced the N2O emission reduction capacity by biochar (p < 0.001), and effect size was as low as -24.32. 700-900 °C biochar can promote CH4 flux but inhibit N2O flux. This study provides an important theoretical basis and valuable strategic guidance for more accurate estimation and improvement of synergistic emission reduction benefits between CH4 and N2O of biochar in CWs.

Scoliosis school screening of 139,922 multi-ethnic children in Dali, southwestern China: A large epidemiological study.

Idiopathic scoliosis (IS) primarily impacts adolescents and requires early intervention to prevent deformity. Early diagnosis and prediction of spine curvature in children could be aided by school scoliosis screening (SSS). In the Dali Bai Autonomous Prefecture, SSS, including 139,922 children from 18 ethnic groups in 8 counties ranging in age from 6 to 18, was carried out. A medical team conducted the screening with inspection, Adam's test, and angles of trunk rotation (ATR). The overall prevalence of suspected scoliosis was 2.37%, with girls (2.5%) more affected than boys (2.0%). Using penalized regression analysis of LASSO, the variable-selection process was conducted to determine the final regression model. The results showed that age, gender, height, BMI, altitude, latitude, ethnicity, and county were all influencing variables for suspected scoliosis, according to the adjusted final model of multi-factor regression analysis. These results provide substantial information and suggestions for preventative and person-centered healthcare interventions for IS.

Efficient extraction, excellent activity, and microencapsulation of flavonoids from Moringa oleifera leaves extracted by deep eutectic solvent.

A deep eutectic solvent (choline chloride (ChCl)-urea) was chosen to extract flavonoids from Moringa oleifera leaves (FMOL), the condition of extraction was tailor-made, under the optimal extraction conditions (material-to-liquid ratio of 1:60 g/mL, extraction time of 80 min, extraction temperature of 80 °C), the highest extraction efficiency reached 63.2 ± 0.3 mg R/g DW, and nine flavonoids were identified. Then, the biological activities including antioxidant activities, antibacterial activities, and anti-tumor activities were systematically studied. FMOL was superior to positive drugs in terms of antioxidant activity. As to DPPH investigation, the IC50 of FMOL and Vc were 64.1 ± 0.7 and 176.1 ± 2.0 µg/mL; for the ABTS, the IC50 of FMOL and Vc were 9.5 ± 0.3 and 38.2 ± 1.2 µg/mL, the FRAP value of FMOL and Vc were 15.5 ± 0.6 and 10.2 ± 0.4 mg TE/g, and ORAC value of FMOL and Vc were 4687.2 ± 102.8 and 3881.6 ± 98.6 µmol TE/g. The bacteriostatic (MICs were ≤ 1.25 mg/mL) activities of FMOL were much better than propyl p-hydroxybenzoate. Meanwhile, FMOL had comparable inhibitory activity with genistein on tumor cells, IC50 was 307.8 µg/mL, and could effectively induce apoptosis in HCT116. Microcapsules were prepared with xylose-modified soybean protein isolate and gelatin as wall materials; after that, the intestinal release of modified FMOL microcapsules was 86 times of free FMOL. Therefore, this study confirmed that FMOL extracted with ChCl/urea has rich bioactive components, and microencapsulated FMOL has potential application in food industry. Supplementary Information: The online version contains supplementary material available at 10.1007/s13399-023-03877-8.

Change in Cobb angle of each segment of the major curve after posterior vertebral column resection (PVCR): a preliminary discussion of correction mechanisms of PVCR.

INTRODUCTION: Posterior vertebral column resection (PVCR) is an effective technique for treating severe rigid spinal deformities, and no other osteotomy is capable for such an excellent corrective effects. The purpose of this study was to discuss the correction mechanisms of PVCR. MATERIALS AND METHODS: Forty-six patients with severe rigid spinal deformities undergoing PVCR were retrospectively analyzed. According to a routine posteroanterior supine entire spine radiograph performed before and after surgery, the major curve at coronal plane was divided into three segments factitiously: upper segment (from the superior endplate of the upper vertebra of the major curve to the inferior endplate of the upper vertebra adjacent to the resected vertebra), middle segment (from the inferior endplate of the upper vertebra adjacent to the resected vertebra to the superior endplate of the lower vertebra of the resected vertebra), and lower segment (from the superior endplate of the lower vertebra of the resected vertebra to the inferior endplate of the lower end vertebra of the major curve). Cobb method was used to measure the curvature of the major curve and each segment. We analyzed the changes of the Cobb angle in the major curve and each segment. We also analyzed the correlation between the placement of pedicle screws and deformity correction. RESULTS: The Cobb angle of the major curve decreased from 110.1 ± 18.1° to 51.0 ± 17.3° (p < 0.05) after surgery (decreased by 59.1 ± 16.4°), the mean correction rate was 54.1 ± 12.2% (p < 0.05). The Cobb angle of the middle segment decreased by 28.1 ± 14.7° (p < 0.05), the contribution rate was 49.1 ± 27.3%. The upper and lower segments decreased by 15.7 ± 13.1° and 15.3 ± 12.4°, respectively (p < 0.05). There were no significant differences in the contribution rate between upper and lower segments (25.2 ± 16.6% vs. 26.3 ± 22.6%) (p > 0.05). 22 patients were instrumented with at least one pedicle screw in the adjacent upper and lower vertebras of the resected vertebra and gained a better corrective effect in comparison with the others (p < 0.05). The data also indicated that deformity correction was closely related to the numbers of the pedicle screws (r = 0.82, p < 0.05). CONCLUSION: In conclusion, the middle segment offered the highest contribution rate to the deformity correction of the major curve, but at the same time the spinal cord was angulated in this segment. So, it is dangerous to gain too much deformity correction in the middle segment. Because spine would shorten and the tension in spinal cord would decrease after vertebral column resection, a better correction effect could be gained in upper and lower segments at a low risk of spinal cord injury. But it was actually too hard for such rigid spinal deformity. It could gain a better corrective effect and stability by placing more pedicle screws at major curve, especially at the upper and lower vertebras adjacent to the resected vertebra, but sometimes it was difficult to place enough pedicle screws in severe rigid spinal deformities.

Posterior Vertebral Column Resection for Severe Spinal Deformity Correction: Comparison of Pediatric, Adolescent, and Adult Groups.

We compared the pre-, intra-, and postoperative characteristics among three groups of patients who underwent posterior vertebral column resection (PVCR) to clarify age-related characteristics and to guide patient management, surgical planning, and complication avoiding. We compared and analyzed the etiology, surgical events, outcomes, and complications among pediatric, adolescent, and adult patients who underwent PVCR in a single-center database retrospectively. Patients were categorized into pediatric (0-12 yr), adolescent (13-19 yr), and adult (>20 yr) cohorts. Demographics, surgical events, clinical and radiographic results, and major complications were compared between groups. A total of 87 patients with a mean follow-up 42 (24-96) months were identified. Pediatric group (14) had a high frequency of congenital vertebral and cardiac abnormal, adolescents (47) presented more intracanal malformations, and idiopathic was common in the adult group (26). Although pediatric patients had shorter fusion levels than adolescent and adult, their mean resected vertebrae (1.91), percentage of blood loss (estimated blood loss per total blood volume) (201.9%), and operative time were much higher. The coronal/sagittal correction rate was significantly higher in the pediatric group (73.6%/72.3%). Overall, surgical complications were more frequent in adults, particularly neuromonitoring alert and implant failure. However, more severe complications were noted in younger patients. For pediatric patients with PVCR, poor physiological conditions and frequent comorbidities indicated cautious patient selection and sufficient preoperative preparation. The higher correction rate may be due to the excellent compliance of the spinal cord. For adult patients, preoperative traction and adjusting the tension of the spinal cord during surgery could contribute to neurological safety.

Is There a Correlation Between Cobb Angle and Pulmonary Function Tests at 2-year Follow-up in Patients With Severe Spinal Deformity Treated by Posterior Vertebral Column Resection?

STUDY DESIGN: A retrospective study. OBJECTIVE: The aim was to evaluate the relationships of Cobb angle and pulmonary function tests (PFTs) changes in severe spinal deformity and underwent posterior vertebral column resection (PVCR). SUMMARY OF BACKGROUND DATA: No previous study focused on the correlation of deformity correction and PFTs changes in patients with cobb angle >90 degrees. METHODS: PFTs values [forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and percent-predicted values FVC%, FEV1%] were evaluated preoperative and at 2 years after PVCR. FVC% <80% were defined as restrictive ventilation dysfunction (RVD), the severity of RVD were divided into mild (FEV1% ≥70%), moderate (70% > FEV1% ≥50%) and severe (FEV1% <50%). The relationships among PFTs values improvements and all possible impact factors (mainly correction cobb angle) collected in this study were analyzed. PFTs data were compared among the 3 RVD subgroups (mild vs. moderate vs. severe) and between residual >30 versus <30 degrees. RESULTS: A total of 53 cases (28 male/25 female, mean ages 18.9 Y) underwent PVCR in one center from 2004 to 2016 were enrolled cobb angle. When 2 years after PVCR, average PFTs values showed significant improvements. PFTs values changes showed no correlation with correction rate and correction angle. The only significant impact factor in this study for FVC, FVC%, FEV1 improvements was preoperative FVC% and the only impact factor for FEV1% improvement was preoperative FEV1%, the relationships were negative. In accordance with the regression analysis, PFTs values improvements among the 3 RVD subgroups from high to low was severe>moderate>mild. However, patients with residual cobb angle <30 degrees had less PFTs values improvements than patients with residual cobb angle >30 degrees. CONCLUSIONS: Two years after PVCR, PFTs values were significantly improved. There is no linear correlation between cobb angle change and PFTs values improvements. Lower preoperative FVC% and FEV1% indicate more PFTs values improvements at 2 years post-PVCR. LEVEL OF EVIDENCE: Level III.

Mid- and Long-Term Comparison Analysis of Two Approaches for the Treatment of Level III or Higher Lenke-Silva Adult Degenerative Scoliosis: Radical or Limited Surgery?

OBJECTIVE: As the population in general is living longer, less invasive adult degenerative scoliosis (ADS) surgery that balances risks and benefits requires long-term clinical outcomes to determine its strengths and weaknesses. We design a retrospective study to compare the postoperative mid- and long-term outcomes in terms of efficacy, surgical complications, and reoperation rate of patients with ADS treated with two different surgical approaches (long-segment complete reconstruction or short-segment limited intervention). METHODS: In this retrospective study, 78 patients with ADS (Lenke-Silva levels III or higher), who accepted surgical treatment at our hospital between June 2012 and June 2019 were included. These patients were assigned to the long-segment radical group (complete decompression with deformity correction involves ≥3 segments) and the short-segment limited group (symptomatic segment decompression involves <3 segments). In addition, general information such as age, gender, fixed segment number, efficacy, radiographic parameters, and reoperation rate of patients in the two groups were compared and analyzed. RESULTS: There were no significant differences between the two groups with regard to gender, follow-up time, long-term surgical complications and reoperation rate (P > 0.05). The mean age of patients in the long-segment strategy group was 57.1 ± 7.9 years, with a mean number of fixed segments of 7.9 ± 2.4. The mean age of patients in the short-segment strategy group was 60.8 ± 8.4 years, with a mean number of fixed segments of 1.4 ± 0.5. At the final follow-up visit, the long-segment radical group showed better results than the short-segment limited group with regard to coronal Cobb angle, lumbar lordosis angle and sagittal balance (P < 0.05). The long-segment strategy group had a higher implant-related complication rate (P = 0.010); the adjacent segment-related complication in the two groups showed no significant difference (P = 0.068). CONCLUSION: Considering the risk, rehabilitation pathway and costs of long-segment radical surgery, short-segment limited intervention is a better strategy for patients who cannot tolerate the long-segment surgery, improving symptoms and maintaining efficacy in the mid- and long-term, and not increasing the reoperation rate.

Posterior Injured Vertebra Column Resection and Spinal Shortening for Thoracolumbar Fracture Associated with Severe Spinal Cord Injury: A Retrospective Case-Control Observational Study.

Background: Thoracolumbar spinal fracture associated with severe spinal cord injury (sSCI) is a kind of severe traumatic spine injury. Although various approaches are currently used to treat sSCI-related thoracolumbar fractures, the neurological function of patients has not been significantly improved by surgery. Objective: To evaluate the therapeutic effects of the new procedure of posterior injured vertebra column resection (PIVCR) and spinal shortening for the treatment of thoracolumbar fracture associated with sSCI. Methods: In this retrospective case-control observational study, we included 66 patients with thoracolumbar fractures associated with sSCI in our institution from January 2015 to December 2017. According to the different surgical approaches, the patients were allocated to group A (n = 32, received simple posterior decompression and fixation) and group B (n = 34, received PIVCR and spinal shortening). All patients' clinical and radiologic outcomes were collected to evaluate retrospectively. The clinical outcomes were gathered, including the intraoperative blood loss, operative time, visual analog scale (VAS) score, and American Spinal Injury Association (ASIA) impairment scale. The radiologic outcomes were collected involving the range of spinal shortening, canal encroachment, heights of the anterior edge of the vertebral body, and the Cobb angle. Results: There was no significant difference in the two groups regarding preoperative demographic data, VAS scores, segmental kyphosis Cobb, canal encroachment, and neurological status. The range of spinal shortening in group B was an average 1.57 ± 0.40 cm and 36.45 ± 6.56% of the height of the single spinal motion segment. Due to the characteristics of the surgical procedure, group B got complete decompression of the spinal cord and better postoperative canal decompression than group A. Thus, better clinical outcomes, including neurological improvement, loss of corrective Cobb angle, and VAS improvement, were shown in group B at the follow-up investigation than those in group A (P < 0.05). Conclusion: PIVCR and spinal shortening surgical procedure is a safe, reliable, and effective approach to treating thoracolumbar fracture associated with sSCI.

Factors Associated with Postoperative Respiratory Complications following Posterior Spinal Instrumentation in Children with Early-onset Scoliosis.

OBJECTIVE: To investigate the incidence and risk factors of postoperative respiratory complications (PRCs) in children with early-onset scoliosis (EOS) following posterior spine deformity surgery (PSDS) based on growth-friendly techniques, so as to help improve the safety of surgery. METHODS: A retrospective study of children with EOS admitted for PSDS based on growth-friendly techniques from October 2013 to October 2018 was reviewed at a single center. There were 73 children (30 boys, 43 girls) who fulfilled the criteria in this research. The mean age of the patients was 7 ± 6.2 years. Patients were divided into the groups with and without PRCs. Variables that might affect the PRCs during the perioperative period, including general factors, radiographic factors, laboratory factors and surgical factors, were analyzed using univariate analysis to evaluate the potential risk factors. The variables that were significantly different were further analyzed by binary logistic regression analysis to identify the independent factors of PRCs. RESULTS: All the 73 children included 42 idiopathic scoliosis (57.5%), 12 congenital scoliosis (16.4%), 10 syndromic scoliosis (13.7%) and nine neuromuscular scoliosis (12.3%). PRCs were detected in 16 children (21.9%) with nine different PRCs. The total frequency of detected PRCs was 54, including pleural effusion (25.9%), postoperative pneumonia (20.4%), hypoxemia (18.5%), atelectasis (14.8%), prolonged intubation with mechanical positive pressure ventilatory support (PIMPPVS) (7.4%), bronchospasm (3.7%), reintubation (3.7%), delayed extubation (3.7%) and pneumothorax (1.9%). Results of univariate testing demonstrated that the following six variables were statistically different (P < 0.05): nonidiopathic scoliosis, combined with pulmonary comorbidities, pretransferrin < 200 mg/dL, prealbumin < 3.5 g/dL, anesthesia time ≥ 300 min and blood loss to total blood volume ratio (BL/TBV) ≥ 15%. Binary logistic regression analysis confirmed that BL/TBV≥15% (odd ratio OR = 29.188, P = 0.010), combined with pulmonary comorbidities (OR = 19.216, P = 0.012), pretransferrin < 200 mg/dL (OR = 11.503, p = 0.024), and nonidiopathic scoliosis (OR = 7.632, P = 0.046) were positively linear correlated with PRCs in children with EOS following PSDS. CONCLUSION: PRCs has a higher incidence in children with EOS following PSDS. BL/TBV ≥15%, combined with pulmonary comorbidities, pre-transferrin < 200 mg/dL, and nonidiopathic scoliosis play an important role for the development of PRCs in this population.

Spinal-Shortening Process Positively Improves Associated Syringomyelia in Patients with Scoliosis After Single-Stage Spinal Correction.

OBJECTIVE: Single-stage spinal correction without previous neurosurgical intervention has been attempted in patients with scoliosis associated with syringomyelia (SM). However, evidence to demonstrate its potential influence on associated SM from direct spinal correction is still lacking. The aim of the present study was to explore the role of spinal shortening in the prognosis of SM-associated scoliosis after single-stage spinal correction without previous neurosurgical intervention. METHODS: Patients with SM-associated scoliosis without previous neurological intervention, who had undergone posterior direct instrumental correction (PDIC) without osteotomy and posterior vertebral column resection (PVCR) at a single center, were selected for comparative analysis. The basic demographic and pre- and postoperative imaging data of the spinal deformity and SM at the final follow-up were compared separately for the 2 different spinal correction procedures. RESULTS: A total of 23 patients were included in the final analysis: 13 had undergone PDIC and 10 had undergone PVCR. The mean follow-up period was 6.2 years (range, 5-9 years). At the final follow-up, the mean corrective rate of scoliosis and kyphosis was 65.7% and 48.4%, respectively. Obvious SM reduction was achieved in 11 patients (47.8%), with an average reduction of 37.3%. No patient experienced neurologic deterioration or had required further neurosurgical intervention for SM during follow-up. The patients who had undergone PVCR had had much more severe scoliosis (98.8° vs. 60.5°; P = 0.000) and kyphosis (74.8° vs. 43.6°; P = 0.032). Moreover, 80.0% of the patients who had undergone PVCR had experienced obvious SM improvement compared with 23.1% of those who had undergone PDIC (P = 0.007). CONCLUSIONS: The reduction of spinal cord tension is an important factor influencing SM improvement. As the most powerful spinal-shortening osteotomy, PVCR can effectively correct severe spinal deformities and improve associated SM. Single-stage posterior spinal correction can be a potential choice for selected patients with scoliosis and untreated SM using strict inclusion criteria, which will not only achieve safe spinal correction but could also steadily improve and stabilize SM.